Found this on <a href="http://del.icio.usdel.icio.us: The Invisible Train by Daniel Wagner, Thomas Pintaric, Florian Ledermann, Dieter Schmalstieg, a cool augmented reality game with a multi-user component:

The Invisible Train is a mobile, collaborative multi-user Augmented Reality (AR) game, in which players control virtual trains on a real wooden miniature railroad track. These virtual trains are only visible to players through their PDA's video see-through display as they don't exist in the physical world. This type of user interface is commonly called the "magic lens metaphor".

Why do I blog this? I like this new trend in augmented reality called "handheld augmented reality": the interface is lighter, the rendering of the scene is done on a (cheap) handheld and (costly) glasses as represented on this picture: This makes game development more realistic (through the lens), the point is now to create games with specific tags as in this case. I'd love to have such a feature on my DS.